Cation Cation: In the fields of chemistry and geochemistry, a cation is a positively charged ion. The oppositely charged ion is an anion.

Extrusive Rocks Extrusive Rocks: In the volcanology branch of geology extrusive rocks are igneous rocks that have been erupted onto the Earth’s surface, before forming and crystallizing. On the other hand, intrusive rocks form and crystallize under the Earth’s ground surface. Extrusive rocks are typically microcrystalline and aphanitic, because of the faster rate of cooling…

Aphanitic Definition Aphanitic: In geology, the term aphanitic describes the texture of plutonic or volcanic igneous rocks, with grains that are not visible to the naked eye. In fact, an aphanitic texture is usually the result of faster cooling and solidification of liquid magma.

Anion Anion: In the fields of chemistry and geochemistry, an anion is a negatively charged ion. The oppositely charged ion is a cation.    

Ultramafic Definition In the study of geology, the term “ultramafic” refers to an igneous rock that comprises up to 90% mafic minerals, or more.